1. Field of the Invention
This invention relates to semiconductor wafer processing, and more particularly to temperature control during wafer coating operations.
2. Background of the Technical Art
During fabrication of an integrated circuit on a semiconductor wafer, it is often necessary to coat an exposed surface of the wafer with a material such as photoresist or insulating material. Wafer coating is often accomplished by attaching the wafer to a chuck and spinning the chuck at a high speed while coating material is deposited on the wafer surface. The chuck is typically driven by a motor spindle of a drive motor. At moderate or high rotational speeds the motor and spindle tend to generate heat, and a portion of this heat can be conducted to the wafer. This can produce non-uniform temperatures on the wafer surfaces and can degrade the quality of the coating process by producing non-uniform coatings on the wafer surface.
In the prior art, the apparatus typically used to remove heat from the motor is a water jacket assembly, which circulates water around the motor to conduct heat away from the motor. However, this apparatus is difficult and expensive to retrofit into existing systems due to the space required, the plumbing required, and the maintenance required to keep it operational.
What is needed is an economical and effective approach that reduces heat transfer from the motor and motor spindle to the chuck and attached wafer to promote uniform wafer coating.